Hyperthermia, when combined with radiation or drugs, has shown both in-vitro and in-vivo to have tremendous potential for human cancer therapy. Experience in our hyperthermia clinic treating 120 patients (1-12 heating sessions each) in which aggressive multipoint thermometry was used, revealed that tumors greater than 2-3 cm in any dimension are very rarely entirely heated to therapeutic temperatures (43-45 degrees C) with presently available equipment. The objective of this work is to develop microwave (MW) heating equipment that will allow more meaningful clinical studies of the efficacy of hyperthermia. A primary intent is to develop MW equipment capable of satisfactorily heating large area superficial (1-3 cm depth) tumors while keeping most of the adjacent normal tissue at 41 degrees C or below. Particular emphasis will be placed on the entire chest wall and axilla region. This equipment will be able to compensate for spatially and time varying conditions, and will couple to contoured surfaces. Development of applicators accessible to body cavities is included. An extensive study of the feasibility of using radiometry as a first step non-invasive temperature monitoring technique useful for power control with versatile surface applicators will be undertaken. Large MW applicators to improve deep heating will be developed. These will be based partly on the knowledge and techniques developed for superficial heating, and have primary concern for the realities of clinical treatments. Comprehensive evaluation techniques and analysis, employing phantoms, live animals (pigs) and clinical treatments will be developed and implemented to evaluate the equipment resulting from seven projects: 1) optimization of radiating microstrip antennae, 2) scanning superficial applicators, 3) MW "blanket," 4) versatile multi-element feedback phase and amplitude power control, 5) "balloon" flexible intracavitary applicators, 6) radiometry-aided power control, and 7) deep heating development.